Modern saddles are designed around a rigid frame called a saddletree. Saddletrees are typically constructed of a nonflexible material such as wood, metal, plastic, or fiberglass. Although these rigid saddletrees may provide an ample basis of support and stability for a rider seated in a saddle, the rigidity may often result in pain or even injuries to the horse carrying the saddle and the rider.
Treeless saddles have recently been developed to address the above concerns. While treeless saddles may not have the same disabling characteristics of traditional treed saddles, providing a treeless saddle with the desired rider support and stability may be a challenge in its design.